Arduino error can't upload the program

[dwiiwan]

why when I upload the program there is a warning

avrdude: ser_open (): can't open device "\\. \ COM6": The semaphore timeout period has expired.

[ballscrewbob]

Could you take a few moments to Learn How To Use The Forum.
It will help you get the best out of the forum in the future.

Posting tips.

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